1. Field of the Invention
The present invention relates to an ion generating element capable of emitting both of positive ions and negative ions into a space and disinfecting bacteria floating in the air, an ion generator using the ion generating element, an air conditioning apparatus, cleaner and refrigerator using the ion generator. The present invention more particularly relates to an ion generating element capable of emitting positive ions and negative ions in a stable manner, reducing noise caused by the emission of ions, and decreasing the emission of ozone by designing a surface electrode formed on a surface of a dielectric body to have a special shape.
2. Description of the Related Art
In general, in a closed room which is ventilated less frequently, such as an office and a conference room, when there are many people in the room, the air polluting substances such as carbon dioxide discharged by breathing, smoke of cigarettes and dust increase, and consequently negative ions which have the effect of relaxing human are reduced in the air. Sometimes a large amount of negative ions are lost by cigarette smoke particularly and the negative ions are reduced to about ½ to ⅕ of the usual amount.
Therefore, a number of ion generators have been sold in the market to supply negative ions into the air, but all the generators just generate only negative ions by a DC high voltage system. Such a conventional ion generator for generating only negative ions can supply negative ions into the air, but can not positively remove the floating bacteria in the air.
The present inventors eagerly studied and, as a result, have invented a structure of emitting H+(H2O)n (n is a natural number) as positive ions and O2−(H2O)m (m is a natural number) to enclose the floating bacteria in the air with the ions, make a chemical reaction, and disinfect the floating bacteria in the air by the decomposition function of hydrogen peroxide (H2O2) and/or hydroxyl radical (·OH) that are active species generated in the chemical reaction.
The applicant of the present application proposed in Japanese Patent Application No. 2001-166118 an ion generating element comprising a surface electrode formed on a surface of a dielectric body, and an inner electrode provided in parallel to the surface electrode inside the dielectric body. FIG. 10 is a perspective view showing the ion generating element, and FIG. 11 is a cross sectional view of the ion generating element. As shown in these figures, a dielectric body 104 made of ceramics is composed of an upper dielectric body 102 and a lower dielectric body 103, and a strip-like inner electrode 106 is formed between the upper dielectric body 102 and the lower dielectric body 103.
On the other hand, on a surface of the upper dielectric body 102, a surface electrode 105 is formed in parallel to the inner electrode 106. The surface electrode 105 is screen-printed using tungsten, on the upper dielectric body 102, and also formed in a grid pattern as shown in FIG. 10 so as to emit a large amount of positive ions and negative ions into the air. In short, the grid-like surface electrode 105 is formed on a surface of the dielectric body 102 by screen printing so as to efficiently generate positive ion and negative ions.
In addition, the ion generating element 101 comprises: a coating layer 109, made of alumina or the like, covering the surfaces of the dielectric body 102 and surface electrode 105; a surface electrode connecting part 111 whose one end is connected to the surface electrode 105 and the other end is connected to a surface electrode contact 108 provided on the lower face of the lower dielectric body 103; and an inner electrode conducting part 112 whose one end is connected to the inner electrode 106 and the other end is connected to an inner electrode contact 107 provided on the lower face of the lower dielectric body 103. By connecting the inner electrode contact 107 and the surface electrode contact 108 to a voltage applying circuit, not shown, and applying an AC voltage to the inner electrode 106 and the surface electrode 105 formed in a grid pattern on a surface of the upper dielectric body 102, a large amount of positive ions and negative ions are generated.
In the ion generating element proposed in Japanese Patent Application No. 2001-166118, however, it is necessary to take a voltage fluctuation during the actual use into account and apply a voltage for satisfactory generation of ions. In other words, the relation between the voltage and ion generation has characteristics that ions are generated by application of a voltage equal to or higher than a certain value and the amount of ions increases with an increase in the voltage, but the ion increase rate decreases when a higher voltage is applied. In a stable region, there is a problem of big discharge sound on the electrode surface, and it is necessary to decrease noise as small as possible in actual application.
Furthermore, since ozone harmful to human body is generated with the generation of ions, it is necessary to decrease the generation of ozone as low as possible while maintaining the emission of ions.
The inventors of the present application conducted experiments repeatedly by changing the conditions of the surface electrode formed on a surface of the dielectric body, and found that it was possible to generate ions from a lower voltage region and generate ions in a stable manner in a wide range of applied voltage by further extending the grid-like surface electrode to form a pointed surface electrode inside the grid squares. Accordingly, since stable ion generation is performed even at a low voltage, the inventors also found that it was possible to reduce noise and the generation of ozone by optimizing the shape and size of the surface electrode.
The present invention has been made based on the findings and with the aim of solving the above problems, and it is an object of the present invention to provide an ion generator capable of generating positive ions and negative ions in a stable manner under a wide range of applied voltage while reducing noise and also capable of reducing the generation of ozone, by forming the surface electrode in a special shape, and to provide an ion generator using the ion generating element.
Moreover, it is another object of the present invention to provide an air conditioning apparatus capable of being incorporated in various apparatuses such as an air conditioner, a microwave oven and a washing/drying machine by using the ion generator of the present invention and a blower for sending ions generated by the ion generator to the outside.
Furthermore, it is still another object of the present invention to provide a cleaner and a refrigerator, capable of effectively reducing dirt in air such as dust generated during cleaning and unpleasant smells in the refrigerator, by installing the ion generator of the present invention and a blower for sending the generated ions out of the cleaner or into the refrigerator.